hi again. nope, that's not what i meant, but thanks 4 your explanation, now i learned something else

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let me try to explain what i'm saying:
imagine a common picture of you with something in the background, lets say, niagara falls. then you reach some tool on photoshop and you load a frame or rectangle you had saved before, this rectangle has a specific shape and size, lets say it's size is approx an ID's photo size. then you place this frame around your face in that picture, after that, you press or select something, and everything gets cropped except what was inside of this frame you loadedm, so now you have no niagara falls and no background and no big photo, just a small photo of your head.
this is not a frame to draw, this is not a frame you're gonna leave marked forever on this image. what i want to know is how to make or create that frame so that when i want to crop a picture, i just load the frame and crop the outside. the main reason i want this: i have 4:3 pictures and i wanna crop them to fit in my 16:9 screen (1440x900), and it's slow and boring to do it in MS Paint, i have to calculate and center the image, rotate it, ando such stuff.
i'd really appreciate if someone could help me, or at least tell me if that's not possible hehe.
thanx